What is the reagent used in Clemmensen reduction?

$Zn-Hg/conc.\, HCl$

The correct answer is Option (3) → $Zn-Hg/conc.\, HCl$

Core Concept

Clemmensen reduction converts aldehydes or ketones into hydrocarbons under strongly acidic conditions.

Detailed Explanation

Clemmensen reduction:

R–CO–R′ → R–CH₂–R′

The carbonyl group is reduced to –CH₂ group using:

Zinc amalgam (Zn–Hg) + concentrated HCl

Option 1: NH₂NH₂

Hydrazine is used in Wolff–Kishner reduction, not Clemmensen reduction.

Option 2: NaOCl

Sodium hypochlorite is an oxidizing agent.

Option 3: Zn–Hg / conc. HCl

This is the correct reagent combination used in Clemmensen reduction.

Option 4: NaHSO₃

Used for aldehyde purification, not reduction.